Selecting COUNT(*) with DISTINCT

Selecting COUNT(*) with DISTINCT: A Guide to Counting Distinct Program Names in SQL Server

👋 Hey everyone! Welcome back to our tech blog. Today, we're going to dive into the common issue of counting distinct program names in SQL Server using COUNT(*) with DISTINCT. Let's get started!

Understanding the Problem

In our scenario, we have a table called cm_production in SQL Server 2005. This table contains data on code that has been put into production, including columns such as ticket_number, program_type, program_name, and push_number.

Our goal is to count the distinct program names by program type and push number. We already have a query, but there's a small issue - it counts all the program names, not just the distinct ones. 🤔

Let's take a look at the existing query provided:

DECLARE @push_number INT;
SET @push_number = [HERE_ADD_NUMBER];

SELECT DISTINCT COUNT(*) AS Count, program_type AS [Type] 
FROM cm_production 
WHERE push_number=@push_number 
GROUP BY program_type

Finding a Solution

To count distinct program names, we need to make a slight adjustment to our query. Instead of using COUNT(*), we'll combine it with the COUNT(DISTINCT column_name) function.

Here's the modified query:

DECLARE @push_number INT;
SET @push_number = [HERE_ADD_NUMBER];

SELECT COUNT(DISTINCT program_name) AS Count, program_type AS [Type] 
FROM cm_production 
WHERE push_number = @push_number 
GROUP BY program_type

🎉 Great! Now we're on the right track. By replacing COUNT(*) with COUNT(DISTINCT program_name), we ensure that only distinct program names are counted.

Understanding the Solution

The COUNT(DISTINCT column_name) function allows us to count the number of unique values in a specified column. In our case, it counts the distinct program names.

By grouping the result using GROUP BY program_type, we can get the count of distinct program names for each program type.

Call-to-Action

That's it for today's guide on selecting COUNT(*) with DISTINCT in SQL Server to count distinct program names. We hope you found this blog post helpful and easy to follow. 🙌

If you have any further questions or additional tricks you'd like to share, please leave a comment below. Let's engage in a fruitful discussion and learn from each other's experiences. 💡💬

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